I just posted a simular question. I have same problem, cannot find setting in BIOS. VirtualBos is checked and so is I/O APCI as per the Sun Documention . Please post anything you find and I will do the same. My Win XP vM runs fine, its when I try installing WIN7 I have a problem.
What client are you using?
Here is as list of VT-x supported Intel Platforms.
I installed VirtualBox on top of Win 7 locally installed OS with Intel VT-x enabled.
64-bit OS installed in VirtualBox sucessfully
32-bit OS installed in VirtualBox sucessfully
If I disable VT-x the 32-bit OS will still run, but the 64-bit will get the error experienced above. Hope the above link for VT-x enabled Intel Platforms helps.
Thank you for your reply, I appreciate it even though it was of no use. I already checked that my processor supports Intel VT-x. My problem is that there is no setting in BIOS to enable it and it is disabled by default. So the question is still open, is there any other way to enable it or the BIOS is the only one?
Unfortunately, you will have to obtain a BIOS upgrade from your vendor.
That's bad news I'm already using the most recent BIOS and it's futile to ask them to create a new, more advanced one with that option built in. They are a sort of... dumb... on answering questions. I asked them if there is any way to enable that feature, because I found no such option in the BIOS. Their answer was that there was no such option in the BIOS Not a single 'We're sorry' or a 'We don't know'. They just simply repeated what I stated before.
i also had this problem on my hp dc7800 (Intel® Core™2 Duo E6550 processor (2.33 GHz, 4 MB L2 cache, 1333 MHz FSB)...
i have enable VTx and VTd on BIOS
BIOS----->Security ------>System Security ------->enable VTx and VTD
after that its worked fine i think this will be helpfull to all